topic RE: Two IPs with different netmask on the same vlan in ExtremeSwitching (EXOS/Switch Engine)

Two IPs with different netmask on the same vlan

gbs — Wed, 22 Feb 2017 02:54:00 GMT

Can i add two ip in the same vlan?

My Black Diamond (BD8810) have his management interface on my vlan50 with netmask 255.255.0.0 (/16) and i have one Cisco that have the same vlan50 with netmask 255.0.0.0 (/8) but for other network.

I want to move the uplink of this other network to my BD. But the users of the other network need to check my "switch" SNMP via vlan50/8.

So, if i can use two VLAN50 ip address, one with /16 and other with /8 mask i can start to remove the cisco switch.

I know that i will have another problem in the future. That is to block all my traffic from VLAN50/16 to go to VLAN50/8 port. We already do this with the cisco switch, by blocking mac addresses.

RE: Two IPs with different netmask on the same vlan

Henrique — Wed, 22 Feb 2017 03:19:00 GMT

Hi Gerson, please see the article below:

https://gtacknowledge.extremenetworks.com/articles/Q_A/Is-it-possible-to-configure-secondary-IP-addr...

An option would be using another Virtual-router (VR)

https://gtacknowledge.extremenetworks.com/articles/Q_A/What-is-a-Virtual-Router

RE: Two IPs with different netmask on the same vlan

Tripathy__Priya — Wed, 22 Feb 2017 09:22:00 GMT

What i feel this feature is not supported on EXOS. Well as stated by Henrique you can avail the facility of using the VR concept. This may help you in achieving the same.

RE: Two IPs with different netmask on the same vlan

gbs — Thu, 23 Feb 2017 01:46:00 GMT

Ok. I'm going to study this feature and try.

Thanks.

RE: Two IPs with different netmask on the same vlan

Jeremy_Gibbs — Thu, 23 Feb 2017 22:35:00 GMT

I am assuming vlan50 on the BD and Cisco switch are different and you don't want the users talking? If that isn't the case, proxy arp might take care of some of this.

RE: Two IPs with different netmask on the same vlan

gbs — Fri, 03 Mar 2017 20:47:00 GMT

@Henrique,
create vlan TEST-VL50 vr "VR-TEST" tag 50

Error: 802.1Q Tag 50 is assigned to VLAN vlan50.

I can't create another vlan using the same vlanID 😕

And i need it to be the same ID "50" because my switch is part of one ring using this tagged vlan.

RE: Two IPs with different netmask on the same vlan

Jeremy_Gibbs — Fri, 03 Mar 2017 23:42:00 GMT

The VID is the vlan, so if you already created it, why would you need to make it again?

RE: Two IPs with different netmask on the same vlan

gbs — Sat, 04 Mar 2017 00:25:00 GMT

Cos, i want to add two ip in the same vlan. And@Henrique told me to create another virtual route.

RE: Two IPs with different netmask on the same vlan

Henrique — Sat, 04 Mar 2017 00:25:00 GMT

Hi Gerson, you can use the same ipaddress/subnet in different VRs. However, you cannot use the same VRID since the vlan table is shared between VRs.

RE: Two IPs with different netmask on the same vlan

Erik_Auerswald — Mon, 06 Mar 2017 17:26:00 GMT

Hi Gerson,

are the two "VLAN 50" networks overlapping? For example, 10.0.0.0/8 and 10.55.0.0/16 are overlapping networks. You cannot use a secondary IP address in this case. In fact, for overlapping IP networks you need different virtual routers (VRs), not just different VLANs.

If the networks are not overlapping, e.g. 10.0.0.0/8 and 172.20.0.0/16, then you can use a secondary IP address on VLAN 50. Please see the GTAC Knowledge article How to add secondary IP address on a VLAN.

To get around the problem of having the same VLAN ID for two networks with overlapping IP address ranges, you could add another switch in front of the BD to translate the VLAN tag, using e.g. port specific VLAN tags. Please see Does EXOS support Port-Specific VLAN Tag? and How to configure port specific tags.

Erik

RE: Two IPs with different netmask on the same vlan

gbs — Mon, 06 Mar 2017 17:26:00 GMT

It worked! Thanks 

RE: Two IPs with different netmask on the same vlan

gbs — Tue, 07 Mar 2017 16:29:00 GMT

Yes, they are overlapping. I want to use my 10G module of BD8810 for that. I will check that port specific vlan tag thing. Thanks.